Conservation tillage implement, system and method

ABSTRACT

A conservation tillage implement having three or more rows of individual coulter wheel assemblies laterally spaced apart and removably mounted on a cultivator frame, a coulter wheel assembly in a given row being staggered with respect to the coulter wheel assemblies in a longitudinally adjacent row. The coulter wheel assemblies may be laterally adjustable and may be mounted to the cultivator frame using a mounting means that permits rotation about a vertical axis. The coulter wheel assemblies may comprise a coil spring having a horizontal spring axis to permit upward deflection in response to impact with an obstacle. Leveling attachments may optionally be mounted to the cultivator frame, along with additional field working tools. The implement is used in the management of crop residue as part of a minimum tillage strategy. The implement is particularly resistant to plugging and can be operated at high speeds without undue damage upon impact with obstacles. Advantageously, the implement can be operated in standing water, as found in the growing of rice.

This application is a divisional of U.S. patent application Ser. No.10/521,804, filed Jan. 21, 2005 (now U.S. Pat. No. 7,762,345, issuedJul. 27, 2010), which is a 371 of International Appln. No.PCT/CA2004/000339, filed Mar. 5, 2004, which claims the benefit of U.S.Provisional Appln. No. 60/451,666, filed Mar. 5, 2003, the contents ofall incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an apparatus, system and method forminimally tilling a field as part of a conservation tillage strategy.More particularly, the present invention relates to an apparatus system,and method for crop residue management.

BACKGROUND OF THE INVENTION

Plant residue is plant material that remains in a field following aparticular growing season. Plant residue includes roots, stem, leavesand seed bearing or enclosing plant structures (e.g. pods, cobs andhusks) originating from plants present in the field during the previousgrowing season (eg: seeded crops, volunteer species and weeds). In orderto plant a new crop in a field, plant residue from the previous cropmust first be dealt with.

When following conventional tillage practices, crop residue is typicallyburied by turning over the soil using, for example, a plow such as amold board plow or a chisel plow, a disc harrow, a field cultivator, oranother suitable field working implement.

Conventional tillage practices have been followed for centuries.However, in recent years, conventional tillage practices have fallen outof favor since the underlying soil exposed during turning is especiallyprone to erosion. Also, for economic reasons, it is desirable to make aminimal number of trips across a field.

Conservation tillage practices have been used to address thedisadvantages of conventional tillage practices. When using conservationtillage practices, crop residue is minimally disturbed prior to plantingand is typically left in the field unburied. Often, a crop is plantedthrough the crop residue using no-till planting techniques and a no-tillplanting implement adapted for that purpose.

One such planting implement comprises a combination of a conventionalplanter and a coulter wheel assembly. There are several examples in theprior art of coulter wheels and coulter wheel assemblies that are usedas part of no-till planting implements. U.S. Pat. No. 5,473,999, issuedon Dec. 12, 1995 to Rawson et al., discloses three coulter wheels in atriangular arrangement. U.S. Pat. No. 5,957,217, issued on Sep. 28, 1999to Gunnink, discloses a strip tillage apparatus comprising a pair ofcoulter wheels rotatably mounted on a walking beam which in turn ispivotally mounted on a frame for mounting on a tool bar of a draftvehicle. U.S. Pat. No. 5,462,124, issued on Oct. 31, 1995 to Rawson,discloses a dual coulter device having a pair of coulter wheels arrangedin a staggered relationship for mounting on a single tool bar. U.S. Pat.No. 6,412,571, issued on Jul. 2, 2002 to Mcilhargey, discloses a coulterwheel assembly comprising a vertical shank having a coiled spring. U.S.Pat. No. 5,649,602, issued on Jul. 22, 1997 to Bruce, discloses acoulter wheel which has wavy acutely angled flutes for greater cuttingperformance.

However, when using no-till planting techniques, crop residue preventsthe soil from drying and warming following, for example, a winter seasonhaving cold temperatures and much precipitation. A farmer is preventedfrom planting a crop until the soil is sufficiently dry and warm.Consequently, the planting of crops is delayed shortening the growingseason and having a potentially adverse impact on crop yields.

A new form of conservation tillage has recently emerged wherein the soilis minimally disturbed prior to planting in order to allow air topenetrate the mat of crop residue. This technique is variously known asminimum tillage, residue management, soil aeration or seedbed aeration.A farm implement is used to cut the crop residue and penetrate a shortdistance into the surface of the soil while lifting the soil verticallyto permit access of air to the soil. This farm implement is sometimesknown as a vertical tillage implement. Examples of such an implement arethe Turbotill™ sold by Great Plains Manufacturing and the Reel Till™sold by McFarlane Manufacturing Company. These purpose-built minimumtillage implements comprise a frame and one or two rows of coulterwheels connected by a gang shaft that is rotatably mounted to theunderside of the implement frame. The implements are designed to cut andsize residue in preparation for planting a field, followed by a seriesof conventional leveling attachments, such as spike harrows (eg: BusterBars™) and/or rotary harrows.

However, the foregoing purpose-built minimum tillage implements sufferfrom several disadvantages. Firstly, since the coulter wheels aremounted on a gang shaft, the spacing of the coulter wheels is closetogether and is not laterally adjustable. When a large amount of cropresidue is present, crop residue can collect between adjacent coulterwheels so that they become plugged, impeding rotation of the gang shaftand causing crop residue to be pushed into a mound by the movement ofthe implement. Secondly, the gangs do not allow for deflection ofindividual coulter wheels in response to impact with obstacles, forexample rocks, potentially resulting in damage to the coulter wheel, thegang shaft, or the implement. Thirdly, the implement is purpose-builtand is only usable for residue management; thus, the farmer must bearthe expense of an extra piece of equipment which lies idle most of theyear.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a conservationtillage implement comprising: a cultivator frame having three or morelongitudinally spaced apart transverse cross-members; a plurality ofindividual coulter wheel assemblies; a mounting means corresponding toeach individual coulter wheel assembly; and, three or morelongitudinally spaced apart rows of laterally spaced apart individualcoulter wheel assemblies, each coulter wheel assembly removably mountedon the frame using the mounting means, a coulter wheel assembly in agiven row being staggered with respect to the coulter wheel assembliesin a longitudinally adjacent row.

According to another aspect of the invention, there is provided a kitfor making a conservation tillage implement as previously described froman existing cultivator frame comprising: a plurality of coulter wheelassemblies; a plurality of mounting means for mounting the coulter wheelassemblies to the cultivator frame; and, a set of instructions formounting the coulter wheel assemblies to the cultivator frame using themounting means.

According to another aspect of the invention, there is provided a methodof assembling a conservation tillage implement comprising: providing acultivator frame have longitudinally spaced apart transversecross-members; providing a plurality of individual coulter wheelassemblies; providing a mounting means for each coulter wheel assembly;and, removably mounting the coulter wheel assemblies to the frame usingthe mounting means to form three or more longitudinally spaced apartrows of laterally spaced apart coulter wheel assemblies, a coulter wheelassembly in a given row being staggered with respect to the coulterwheel assemblies in a longitudinally adjacent row.

According to another aspect of the invention, there is provided a systemfor conversion of a field working implement between a conservationtillage implement and a conventional tillage implement, the systemcomprising: a cultivator frame having longitudinally spaced aparttransverse cross-members; three or more longitudinally spaced apart rowsof laterally spaced apart individual coulter wheel assemblies or fieldworking tools removably mounted to the frame; and, the conversioncomprising exchanging field working tools with coulter wheel assemblies,or, exchanging coulter wheel assemblies with field working tools.

According to another aspect of the invention, there is provided a systemfor mounting a coulter wheel assembly to a cultivator frame comprising:a mounting means comprising opposed first and second flanges forclamping engagement with the frame and a vertically extending hollowstrut secured to the first flange, the strut having a pair of opposedhorizontal slots therethrough; and, a coulter wheel assembly comprisinga vertical shank having a horizontal hole therethrough, the shanksecured within the hollow strut by means of a pin extending through theslots and the hole to thereby permit rotational movement of the shankwithin the hollow strut about a vertical axis.

According to another aspect of the invention, there is provided a methodof conservation tillage comprising: providing a field containingstanding water, wet soil, and crop residue; providing a conservationtillage implement comprising spaced apart rows of staggered individualcoulter wheel assemblies; and, operating the conservation tillageimplement in the field through the standing water to cut and size thecrop residue.

According to another aspect of the invention, there is provided a methodof conservation tillage comprising: providing a field containing cropresidue; providing a conservation tillage implement comprising spacedapart rows of staggered individual coulter wheel assemblies; and,operating the conservation tillage implement at speeds in excess of 8miles per hour to cut and size the crop residue.

The use of individual coulter wheel assemblies provides severaladvantages as compared with gang-shaft mounted coulter wheels.Maintenance is simplified, as the individual coulter wheel assembliesmay be readily replaced without removal of the entire gang shaft.Individual coulter wheel assemblies may be staggered; this reduces thelikelihood of plugging with wet soil or crop residue as compared withgang-shaft mounted coulter wheels. The lateral spacing between adjacentassemblies may be adjusted according to soil or crop residue conditions,further reducing the likelihood of plugging. Since plugging is unlikelyto occur, scraper blades are not required for the coulter wheelassemblies; this reduces maintenance and further reduces pluggingproblems as compared with gang-shaft mounted coulter wheels. Individualcoulter wheel assemblies may be permitted to deflect upwardly inresponse to impact with obstacles, as opposed to deflection of an entiregang shaft. This permits the conservation tillage implement to beoperated at faster speeds without impact damage. Since each coulterwheel is permitted to spin at a different rate, the implement may beturned at the end of a field while the coulter wheels are engaged withthe soil; in comparison, coulter wheels at the ends of a gang-shaft aresubjected to shear stresses upon turning when engaged with the soil,leading to pre-mature failure. The ability to turn quickly at the end ofa field is enhanced if the coulter wheel assemblies are mounted in amanner that permits rotation of the assembly about a vertical axis,which is not a practical option for gang-shaft mounted coulter wheels.Using individual coulter wheel assemblies saves space overall, allowingmultiple rows of coulter wheel assemblies to be mounted on a cultivatorframe; this increases the number of times the residue is hit by acoulter wheel as compared with gang-shaft mounted coulter wheels.

A conservation tillage implement is differentiated from a conventionaltillage implement in several ways. A conservation tillage implement isused in no-till or minimum tillage applications and is operated atshallow depths whereas a conventional tillage implement is used forworking and turning the soil and is operated at deeper depths. Inoperation, the conservation tillage implement may be drawn at fasterspeeds and by a tractor with less horsepower as compared with aconventional tillage implement.

The conservation tillage implement of the present invention may be usedon a field just after harvest in the fall to break up crop residue,without tilling the earth, to reduce exposure of the soil to winterelements while cutting and sizing the residue to aid in decompositionand conditioning the soil in preparation for planting the next spring.The conservation tillage implement may be operated at depths of 4-6″when used in the fall for residue management. Alternatively, theconservation tillage implement may be operated on frozen soil to cut andsize residue without appreciably working the soil. Also, the implementmay be used in the spring for seedbed preparation and soil conditioningat about the time of the thaw while the ground is still hard enough tosupport a tractor but before the ground is dry enough to plant a crop.Use of the implement in the spring further breaks up crop residue andalso helps aerate the soil. Aeration of the soil in the spring permitswarm air to enter the soil to expedite thawing and to bring the soil upto planting temperature sooner than it would be otherwise. This allowsthe farmer to plant earlier and to maximize the growing season toincrease yield and productivity. The conservation tillage implement maybe operated at depths of as little as 1″ for seed bed preparation. Theconservation tillage implement may also be used prior to liquid manureapplication for light tillage and residue fluffing, or for incorporationof liquid manure following application. Other uses include: soilleveling; surface crust breaking following heavy rains; encouragement ofweed emergence prior to fall burn down; and, improved insect and diseasecontrol through residue sizing and disturbance.

Advantageously, a conservation tillage implement according to thepresent invention may be drawn at faster speeds than other conservationtillage implements or conventional tillage implements. Although there isno theoretical upper limit on speed, the conservation tillage implementaccording to the present invention may be operated at speeds of from8-18 miles per hour, preferably from about 8-12 miles per hour. Otherconservation tillage implements comprising gang-shaft mounted coulterwheels are typically drawn at speeds of from 6-8 mph, and conventionaltillage implements (for example, field cultivators) are typically drawnat speeds of less than 6 mph. Operating at faster speeds causes the cropresidue to be cut more finely and reduces the likelihood of becomingstuck in wet soil conditions. Fast operational speeds are made possiblein part due to a lack of plugging and low incidence of damage due toimpact with obstacles, both of which result from staggered individualcoulter wheel assemblies.

Surprisingly, a conservation tillage implement according to the presentinvention may be operated in extremely wet soil conditions withoutplugging, even through standing water. This is of particular utility inthe cutting and sizing of crop residue from rice farming operations.Heretofore, attempts to utilize other conservation tillage implements orconventional tillage implements have resulted in plugging of the fieldworking tools, particularly gang-shaft mounted coulter wheels, with mudand crop residue. This necessitated drainage of the rice fields anddrying of the soil prior to working the field and planting the nextsuccessive rice crop. Advantageously, the conservation tillage implementaccording to the present invention can be operated through standingwater without plugging, obviating the need for draining and drying thefield. This is in part due to the staggered individual coulter wheelassemblies and due to high operational speeds, which reduce thelikelihood of becoming stuck. Impact with non-visible submergedobstacles does not result in damage to the implement and does not causethe operator to stop and become stuck. The conservation tillageimplement may be operated at speeds of from 8-15 miles per hour instanding water. The standing water may have a depth of from 0.5-12inches and may cover substantially the entire field.

The coulter wheel assemblies may be mounted to any part of thecultivator frame. For example, the coulter wheel assemblies may bemounted on the transverse cross-members of the frame. The coulter wheelassemblies may be fixed in a particular position on the transversecross-members or they may be laterally adjustable on the transversecross-members. Being laterally adjustable allows the farmer to set adesired distance between the individual coulter wheel assemblies in agiven row. Being able to laterally adjust spacing between coulter wheelassemblies in a given row is advantageous since it decreases thelikelihood of plugging and allows a farmer to adapt the implement tospecific soil types, moisture conditions, or crop residue conditions.Any number of transverse cross-members may be present. Transversecross-members do not need to be continuous from one side of thecultivator frame to the other. It is possible to have a plurality oftransverse cross-members aligned along a common transverse axis butspaced apart laterally. Transverse cross-members that are laterallyaligned along a common transverse axis may be considered for descriptivepurposes as the same transverse cross-member.

The implement comprises three or more rows of coulter wheel assemblies.Thus, the implement may comprise four or more rows, five or more rows,six or more rows, seven or more rows, etc. Usually, there may be threeto eight rows; more particularly, there may be three to six rows. Sixrows and eight rows of coulter wheel assemblies are of particular note.A row may comprise a single coulter wheel assembly or a plurality ofcoulter wheel assemblies. Coulter wheel assemblies are in the same roweven if they are mounted on different transverse cross-members, providedthe coulter wheel assemblies are aligned along a common transverse axis.Thus, coulter wheel assemblies mounted along a common transverse axisform a row. The coulter wheel assemblies may be longitudinally spacedapart from the transverse cross-members. For example, the coulter wheelassemblies may be mounted to longitudinal extension members mounted tothe transverse cross-members of the frame. In this manner, coulter wheelassemblies from more than one row may be mounted to the same transversecross-member, so that a plurality of rows is provided for a giventransverse cross-member.

The coulter wheel assemblies are preferably staggered between adjacentrows so that no two coulter wheel assemblies on longitudinally adjacentrows are in the same longitudinal line. This helps prevent plugging. Acoulter wheel assembly in a row two or more rows removed from a firstrow may or may not be in the same longitudinal line as a coulter wheelassembly in the first row. For example, every second row could have thesame longitudinal alignment of coulter wheel assemblies, or every thirdrow could have the same longitudinal alignment, or every fourth row,etc. Preferably, all of the coulter wheel assemblies in a given row arelaterally staggered with respect to all of the coulter wheel assembliesin a longitudinally adjacent row. If the coulter wheel assemblies arelaterally adjustable on the cross-members, the farmer can use whateverarrangement of staggered rows that is most useful for the particularsoil, moisture, or residue conditions. Lateral spacing between coulterwheel assemblies does not need to be consistent between rows; thelateral spacing can be totally random, provided a staggered effect ispreserved.

Any suitable coulter wheel assembly may be used as part of the presentinvention, provided that the assembly is adapted to be removably mountedon a cultivator frame. The coulter wheel assembly is preferablypositioned so that the coulter wheel is aligned with the direction oftravel to help reduce tractor power requirements. The coulter wheelassembly may comprise a spring element that permits upward deflection ofthe coulter wheel in response to impact with obstacles. The springelement may comprise, for example, a substantially C-shaped spring, aleaf spring, or a coil spring mounted on an upwardly extending shaftthat is deformed upon deflection of the coulter wheel. Preferably, thecoulter wheel assembly disclosed in U.S. Pat. No. 6,412,571, thedisclosure of which is hereby incorporated by reference, may be used.This coulter wheel assembly comprises a coil spring with a horizontalspring axis having upper and lower shank members extending tangentiallytherefrom. In operation, the lower shank member is permitted to deflectupwardly in response to impact with an obstacle, thereby reducing theload transmitted to the mounting means and reducing the likelihood ofdamage to the coulter wheel assembly and the implement.

Any suitable mounting means may be used to removably mount theindividual coulter wheel assemblies on to the cultivator frame. Themounting means may comprise, for example, a bracket that may be used tomount the coulter wheel assemblies on to the transverse cross-members ofthe frame. Although the mounting means may be fixed to the frame (forexample, by welding or bolting), the mounting means preferably permitslateral adjustment of the coulter wheel assembly. The mounting means mayinclude a clamping means having first and second flange members forclamping engagement with the top and bottom of a frame member. The firstand/or second flange may be attached to a vertically extending hollowstrut for receiving, for example, an upper shank member of the coulterwheel assembly. The mounting means may permit rotational movement of thecoulter wheel assembly about a vertical axis. This allows the coulterwheel assembly to move in response to directional changes of theimplement, thereby reducing the load transmitted to the mounting meansand further reducing the likelihood of damage to the coulter wheelassembly and the implement. Rotational movement about a vertical axisalso facilitates turning the implement at the end of the field with thecoulter wheels fully engaged with the ground without causing unduegouging of the earth or damaging the implement.

Due to the possibility for rotational movement of the coulter wheelassemblies about a vertical axis, the implement is not constrained tomovement in a straight line direction and may have a tendency to steermore widely than desired when turned at the end of a field. This may beaddressed by providing a portion of the mounting means without the meansto permit rotational movement of the coulter wheel assembly. Also, if acoulter wheel assembly having a coil spring with a horizontal springaxis is used, it is desirable to orient the coils oppositely on oppositesides of the implement to help alleviate any potential problem ofsideways drift that may occur during operation. Put differently, ifcoils that are wound clockwise are provided on one side of theimplement, coils that are wound counter-clockwise should be provided onthe opposite side of the implement.

Any suitable coulter wheel may be used in a coulter wheel assembly.Although any suitable number of coulter wheels may be provided as partof an individual coulter wheel assembly, it is preferable that a singlecoulter wheel is provided, as this increases flexibility in coulterwheel spacing. The coulter wheel is typically vertical, although it maybe placed at an angle to the vertical in certain conditions. A straightcoulter wheel or preferably a fluted coulter wheel may be used; thesetypes of coulter wheels are well-known in the art. A coulter wheel withwavy acutely angled flutes may be used; for example, the coulter wheeldisclosed in U.S. Pat. No. 5,649,602, the disclosure of which is herebyincorporated by reference. This type of coulter wheel comprises aplurality of waves, each wave comprising a crest and valley oriented atan acute angle to the radius of the wheel. The angle is selected sothat, in operation, the crest and valleys enter the soil with a nearlyvertical orientation in an effort to reduce the power required to drawthe implement.

The cultivator frame is advantageously a standard cultivator frame,although it is possible to use a specially designed frame. Any suitablecultivator frame may be used. For example, the cultivator frame couldcomprise a plurality of longitudinal and transverse rectangular steeltubes formed into a generally rectangular frame, for example by welding,the frame having ends and sides. The transverse rectangular steel tubesof the frame may be the transverse cross-members on which the coulterwheel assemblies are mounted. The frame may comprise a central portionwith two sides and a wing portion hingedly attached to each side, eachwing portion having a corresponding hydraulic cylinder means mounted tothe central portion and each wing portion able to pivot from ahorizontal ground working orientation to a vertical transportorientation upon actuation of the hydraulic cylinder means.Alternatively, the cultivator frame may comprise a plurality oftransverse cross-members on a center spine. The cultivator frame isequipped with a coupling mechanism, or tongue, for hitching thecultivator frame to a draw bar of a tractor. The cultivator frame mayadditionally be equipped with a rear coupling mechanism for hitchingadditional implements to the rear of the frame.

The cultivator frame further comprises a set of wheels to facilitatemovement of the frame over the ground. The set of wheels is heightadjustable to adjust the depth at which the implement is operated. Anysuitable means may be used to adjust the wheel height, for example,hydraulic cylinders, etc. Preferably, the wheels are provided in pairsthat are longitudinally spaced apart. Each pair of wheels may be mountedon a longitudinal axle mounting member that is mounted to the frame at apoint between the wheels, allowing the wheels to pivot in response toobstacles. This is commonly known as a walking axle arrangement. Thewheels in each pair may be staggered and may be mounted on oppositesides of the axle mounting member. The walking axle arrangement allowsthe implement to traverse obstacles or ruts in the field one wheel at atime, thereby reducing the likelihood of jarring the implement andcausing damage thereto as compared with wheels arranged in a row. Thewalking axle arrangement thereby allows the implement to be operated atfaster speeds without suffering mechanical damage. In addition,staggering the wheels reduces the likelihood of plugging between thewheels with mud, which is particularly advantageous in wet soilconditions and when operating the apparatus through standing water.

A conservation tillage implement may further comprise, in addition tothree or more staggered rows of coulter wheel assemblies, one or moreindividual field working tools. The field working tools may comprise,for example, S-tine assemblies or C-shaped shank assemblies. The fieldworking tools may comprise a shank member and a ground engaging member.The shank member may comprise a spring element. The ground engagingmember may comprise a chisel plow point, a triangular or V-shapedshovel, or a sub-soiling tooth. A field working tool may also bereferred to as a tillage tool. A plurality of different types of fieldworking tools may be provided in a given row and the field working toolsmay be interspersed with coulter wheel assemblies. The field workingtools may be located in longitudinally spaced apart rows. The fieldworking tools may be laterally adjustable. The field working tools in agiven row may be staggered with respect to other field working tools orcoulter wheel assemblies in a longitudinally adjacent row. The selectionof the appropriate type, number, or spacing of field working tools orcoulter wheel assemblies is at the discretion of the farmer and may bebased upon the soil, crop residue, or moisture conditions.

Field working tools may be mounted on the cultivator frame by anysuitable means. For example, the field working tools may be bolteddirectly to the frame, clamped to the frame, or attached to the frame bya mounting means. A mounting means similar to the one previouslydescribed in the removable mounting of coulter wheel assemblies may beused. The field working tools may be mounted to the transversecross-members of the frame and/or may be mounted using longitudinalextension members so that the field working tools are longitudinallyspaced apart from the transverse cross-members.

The conservation tillage implement may also comprise conventionalleveling attachments at the rear of the cultivator frame. The levelingattachments may be mounted to a rear transverse cross-member of theframe. Conventional leveling attachments may comprise, for example,spike harrows, leveling bars, rotary harrows, etc., which are draggedbehind the cultivator frame to level the field after the field is workedby the coulter wheel assemblies or other field working tools.Conventional leveling implements (for example, a rotary packer) mayadditionally or alternatively be hitched to the rear of the conservationtillage implement using the rear coupling mechanism.

A conservation tillage implement may be assembled according to thefollowing method. A cultivator frame is provided having longitudinallyspaced apart transverse cross-members. The cultivator frame may be anexisting cultivator frame or one provided especially for the purpose ofassembling a conservation tillage implement. A plurality of coulterwheel assemblies are provided along with a mounting means for mountingeach coulter wheel assembly to the cultivator frame. The coulter wheelassemblies are then removably mounted to the cultivator frame using themounting means to form three or more longitudinally spaced apart rows oflaterally spaced apart coulter wheel assemblies. The coulter wheelassemblies are positioned on the frame such that coulter wheelassemblies in a given row are staggered with respect to coulter wheelassemblies in a longitudinally adjacent row. The method may be performedin conjunction with a kit to create a conservation tillage implement.

A kit may be provided to make a conservation tillage implement from anexisting cultivator frame. The kit may comprise: a plurality of coulterwheel assemblies; a plurality of mounting means for mounting the coulterwheel assemblies to the cultivator frame; and, a set of instructions formounting the coulter wheel assemblies to the cultivator frame using themounting means. The instructions may provide for the mounting of coulterwheel assemblies in three or more longitudinally spaced apart rows andfor staggering the coulter wheel assemblies in a given row with respectto the coulter wheel assemblies in a longitudinally adjacent row. Theinstructions in the kit may include the steps of the method. Anysuitable number of coulter wheel assemblies may be provided as part ofthe kit. The coulter wheel assemblies are mounted to the existingcultivator frame using the mounting means provided with the kit. Thenumber of mounting means is at least equal to the number of coulterwheel assemblies. A conservation tillage implement comprising additionalfield working tools may be created using the kit. In order to installthe coulter wheel assemblies on an existing cultivator frame, the groundclearance of the frame may need to be increased. The kit may furthercomprise stilt means for increasing the ground clearance of the frameand instructions for installation of the stilt means. Hydraulic cylindermeans with a longer stroke length than any existing hydraulic cylinderson the cultivator frame may also be provided as part of the kit.

The kit may be used in the conversion of a conventional tillageimplement to a conservation tillage implement, although the conversionmay also be performed without the kit. A conventional tillage implementcomprising a cultivator frame and a plurality of field working tools maybe converted to a conservation tillage implement by exchanging some orall of the field working tools with coulter wheel assemblies to formthree or more rows of staggered coulter wheel assemblies. The reverseconversion from a conservation tillage implement to a conventionaltillage implement may also be performed. A stilt means and/or hydrauliccylinder means may be employed in the conversion, depending on theground clearance of the cultivator frame. The method of assemblingdescribed above may be employed in the conversion of a conventionaltillage implement to a conservation tillage implement and mayadditionally comprise the steps of removing some or all of the existingfield working tools from the conventional tillage implement. In thismanner, an existing conventional tillage implement can be retrofittedwith coulter wheel assemblies, thereby reducing a farmer's expense inobtaining the conservation tillage implement.

The conversion provides a number of practical advantages. A singlecultivator frame is used for both the conventional tillage implement andthe conservation tillage implement; this results in considerable costsavings to the farmer, since an extra piece of purpose-built equipmentis not needed. There is no timing conflict between the conservationtillage and conventional tillage operations, since these operations areperformed at different times of the year. In addition, dealers can stockframes and components separately and can build either a conventional ora conservation tillage implement on demand, thereby reducing inventorycosts and delivery time. A single, multi-purpose implement provided bythe system of the present invention offers great flexibility and costsavings to the farmer, dealers, and equipment manufacturers.

A system for mounting a coulter wheel assembly to a cultivator framecomprises a mounting means as previously described that permitsrotational movement of the coulter wheel assembly about a vertical axis.The coulter wheel assembly has an upper shank that is inserted into thehollow strut and secured therewithin by means of a horizontal pinextending through a hole in the upper shank member and through opposedhorizontal slots in the strut. The coulter wheel assembly may be removedfrom the mounting means by removal of the pin. The rotational movementof the coulter wheel assembly is constrained by the slot. The rotationalmovement may be constrained so as not to exceed the maximum turningradius of the conservation tillage implement. The rotational movementmay be constrained to +/−30°, preferably +/−23°. The mounting means maybe mounted to the frame by clamping and may be removed from the frame.The system may be employed by first installing the mounting means on theframe, then installing the coulter wheel assembly within the mountingmeans; alternatively, the mounting means may be first installed on thecoulter wheel assembly, then installed on the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, preferredembodiments thereof will now be described in detail by way of example,with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a cultivator frame for use with thepresent invention; g

FIG. 2 a is a front view of a left-side coulter wheel assembly for usewith the present invention;

FIG. 2 b is a front view of a right-side coulter wheel assembly for usewith the present invention;

FIG. 3 is a side view of the left-side coulter wheel assembly of FIG. 2a with a mounting means for use with the present invention;

FIG. 4 is a top view of the left-side coulter wheel assembly andmounting means of FIG. 3 with a fluted coulter wheel;

FIG. 5 is a side-sectional view of the mounting means of FIG. 3;

FIG. 6 is a perspective view of an embodiment of a conservation tillageimplement of the present invention;

FIG. 7 is a top view of another embodiment of a conservation tillageimplement of the present invention;

FIG. 8 is a perspective view of another embodiment of a conservationtillage implement of the present invention, further comprising S-tineassemblies;

FIG. 9 is a perspective view of a C-shaped shank assembly for use withthe present invention;

FIG. 10 is a perspective view of another embodiment of a conservationtillage implement of the present invention, further comprising theC-shaped shank assembly of FIG. 9;

FIG. 11 is a top view of the embodiment of the conservation tillageimplement shown in FIG. 7, further comprising leveling attachmentsmounted to the rear of the frame;

FIG. 12 is a side view of another embodiment of a conservation tillageimplement, further comprising leveling attachments mounted to the rearof the frame and a rear coupling mechanism; and,

FIG. 13 is a side view of an alternative coulter wheel assembly for usewith the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Throughout the description, like reference numerals will be used torefer to like features of the invention.

Referring to FIG. 1, a cultivator frame comprises a plurality oflongitudinal 10 and transverse 11 rectangular steel tubes weldedtogether to form a generally rectangular structure. The cultivator framecomprises a central portion, generally denoted as 12, and two wingportions, generally denoted as 13. Each wing portion 13 is attached to aside of the central portion 12 by means of hinges 14. Each wing portion13 has a corresponding hydraulic cylinder means 15 mounted to thecentral portion 12 and operatively connected to each wing portion. Eachwing portion 13 is able to pivot from a horizontal ground workingorientation to a vertical transport orientation upon actuation of thehydraulic cylinder means 15.

The cultivator frame has a set of wheels comprising four laterallyspaced apart pairs of wheels 20. Only one such pair of wheels is labeledin detail. Each pair of wheels 20 comprises a first wheel 21 that islongitudinally spaced apart and laterally staggered with respect to asecond wheel 22. Each wheel is mounted to a stub axle member (23, 24,respectively) that is attached to a longitudinal axle mounting member25. This is commonly referred to as a walking axle arrangement. A leverarm 26 is pivotally attached at its lower end to the longitudinal axlemounting member 25 between the first wheel 21 and the second wheel 22.The lever arm 26 is also pivotally attached at its upper end to theframe at wheel hinge 27. An upright stanchion 28 is pivotally attachedto the wheel hinge 27. A constraint arm 29 is pivotally attached to anupper portion of the stanchion 28. Hydraulic wheel cylinder 30 ispivotally attached at its lower end to the lever arm 26 and at its upperend to the upper part of the stanchion 28. To raise the frame, the wheelcylinder 28 is extended, causing the lower end of the lever arm 26 toarcuately move downwardly. This causes the frame to rotate upwardlyabout the pivot point of the lever arm 26 with the longitudinal axlemounting member 25. The movement of the frame in turn causes the upperpart of the stanchion 28 to pivot downwardly as the frame movesupwardly. The pivoting of the stanchion causes the upper end of thehydraulic wheel cylinder 30 to move forwardly, thereby maintaining asuitable angle between the hydraulic wheel cylinder 30 and the lever arm26 so that the cylinder has sufficient mechanical advantage to continuethe pivoting action of the lever arm 26. The use of the stanchion 28allows a hydraulic wheel cylinder 30 to be used that has a shorterstroke than would otherwise be necessary to attain the desired range offrame heights.

The cultivator frame has a coupling mechanism 31 at the front thereoffor hitching the implement to the drawbar of a tractor (not shown). Thecoupling mechanism 31 is pivotally attached to the frame at tongue hinge32. A tongue constraint (which has been omitted for clarity) ispivotally attached to the coupling mechanism 31 at constraint hinge 33.The tongue constraint prevents the coupling mechanism 31 from droopingand maintains a desired angular relationship between the couplingmechanism 31 and the frame. A plurality of rear mounting flanges 34 areprovided for mounting of leveling attachments (not shown) to the rear ofthe frame.

The frame further comprises a plurality of longitudinal frame members 40and transverse cross-members 41, only some of which are labeled,attached to the longitudinal 10 and transverse 11 rectangular steeltubes. In some cases, the longitudinal frame members 40 and transversecross-members 41 are supported at both ends, whereas in other cases theyare cantilevered. Coulter wheel assemblies (not shown in FIG. 1) andfield working tools (not shown in FIG. 1) may be mounted to thelongitudinal frame members 40 and the transverse cross-members 41. Insome instances, a plurality of transverse cross-members 41 are alignedalong a common transverse axis.

FIGS. 2 a and 2 b show examples of left and right-side coulter wheelassemblies, respectively, that may be used in the present invention.These coulter wheel assemblies are similar to those described in U.S.Pat. No. 6,412,571. Each coulter wheel assembly 50 comprises a shankhaving a coil spring portion 51, an upper shank portion 52 and a lowershank portion 53, both shank portions extending tangentially from thecoil spring portion 51. The coil spring portion 51 has a horizontalspring axis passing therethrough and permits the upper and lower shankportions 52, 53 to move relative to one another about the spring axis,for example in response to impact with obstacles. When viewed from theleft, the coil spring of the left-side coulter wheel assembly (shown inFIG. 2 a) is wound counter-clockwise, whereas the coil spring of theright-side coulter wheel assembly (shown in FIG. 2 b) is woundclockwise. The upper shank portion 52 is for mounting the coulter wheelassembly to the cultivator frame. The lower shank portion 53 has arotatable hub 54 rotatably attached thereto. A coulter wheel 55 ismounted to the rotatable hub 54.

Referring to FIGS. 3 and 4, the coulter wheel assembly of FIG. 2 a isshown with a mounting means, generally denoted as 60, for mounting thecoulter wheel assembly to one of the transverse cross-members 41.Although a straight coulter wheel 55 is shown in FIG. 3, a flutedcoulter wheel 55 may also be used with the coulter wheel assembly, asshown in FIG. 4. The coil spring 51 permits the lower shank portion 53to deflect upwardly about the horizontal spring axis in response toimpact with obstacles.

The mounting means 60 comprises a vertically extending hollow strut 61for receiving the upper shank portion 52. The hollow strut 61 has twoopposed horizontal slots 62 for alignment with a horizontal hole in theupper shank portion 52. A bolt or pin 63 is inserted through the slots62 and the hole in the upper shank member to secure the upper shankportion 52 within the hollow strut 61, thereby attaching the coulterwheel assembly 50 to the mounting means 60. The horizontal slots 62permit the coulter wheel assembly 60 to rotate about a vertical axisaligned with the upper shank portion 52 and the hollow strut 61. Theslots 62 are sized so that the rotation of the coulter wheel assembly 50is limited by engagement of the pin 63 with the ends of the slots to anangle a corresponding to the maximum turning angle of the implementwithout interference between the coupling mechanism and the tractor. Inthe embodiment shown, the angle a is 23.degree. The hollow strut 61 issecured to a first flange 64 and slidably fitted with a second flange65. In an alternative embodiment, the hollow strut 61 may be secured toboth the first and second flanges 64, 65. The first and second flanges64, 65 are positioned above and below the transverse cross-member 41 andclamped thereto by tightening of lag bolts 66. Loosening lag bolts 66allows the position of the mounting means 60 and coulter wheel assembly50 to be laterally adjusted on the transverse cross-member 41.

FIG. 5 shows a sectional view of the mounting means 60. The upper shankmember 52 (not shown in FIG. 5) is inserted within the hollow strut 61until it engages upper cap 67. The upper cap 67 is welded to the hollowstrut 61 and receives the majority of the upward force when the coulterwheel assembly 50 is engaged with the ground. The pin 63 (not shown inFIG. 5) is thereby permitted to ride freely within the slot 62. Theinterior of the hollow slot 61 comprises ring-shaped recesses forreceiving bushings 68. The bushings 68 are made of agraphite-impregnated nylon material and provide a dry lubricant surfaceagainst which the upper shank member 52 (not shown in FIG. 5) rotates.The bushings 68 are wear-resistant, do not require grease, and are notreadily fouled by dust.

Turning to FIG. 6, an embodiment of a conservation tillage implement ofthe present invention is described with reference to elements of FIGS.1-5. The cultivator frame is the frame described with reference to FIG.1 and functions in the same manner. Individual coulter wheel assemblies50 are removably mounted to transverse cross-members 41 using mountingmeans 60, only some of which are labeled. The coulter wheel assemblies50 are laterally spaced apart and are mounted in longitudinally spacedapart rows. All of the coulter wheel assemblies 50 in a given row arelaterally staggered with respect to all of the coulter wheel assembliesin a longitudinally adjacent row. For each row of coulter wheelassemblies, a plurality of transverse cross-members 41 are aligned alonga common transverse axis.

In FIG. 7, another embodiment of a conservation tillage implement of thepresent invention is described with reference to elements of FIGS. 1-5.Individual coulter wheel assemblies 50 are removably mounted totransverse cross-members 41 using mounting means 60, only some of whichare labeled. Eight longitudinally spaced apart rows of laterally spacedapart individual coulter wheel assemblies 50 are shown. Some of thetransverse cross-members 41 are shown without coulter wheel assemblies50. When viewed from the front of the implement, the left side (which ison the right when viewed from above) has left-side coulter wheelassemblies (as shown in FIG. 2 a) and the right side (which is on theleft when viewed from above) has right-side coulter wheel assemblies (asshown in FIG. 2 b). A longitudinal extension member 70 is shown mountedto a transverse cross-member 41. A coulter wheel assembly 50 is mountedto the longitudinal extension member 70 by mounting means 71. Themounting means 71 is similar to the mounting means 60 in all respectsexcept that the horizontal slots 62 are transposed 90.degree. about thevertical axis. This allows rotational movement of the coulter wheelassembly 50 attached to the mounting means 71 to be in a similar angularrelationship to the rotational movement of the other coulter wheelassemblies about the vertical axis. The longitudinal extension member 70may be of any length and permits two or more rows of coulter wheelassemblies 50 to be mounted to the same transverse cross-member 41. Aplurality of rear mounting flanges 34 are provided for the optionalmounting of leveling attachments (not shown in FIG. 7) to the rear ofthe frame.

In FIG. 8, another embodiment of a conservation tillage implement of thepresent invention is described with reference to elements of FIGS. 1-5.The cultivator frame is the frame described with reference to FIG. 1 andfunctions in the same manner. Individual coulter wheel assemblies 50 areremovably mounted to transverse cross-members 41 using mounting means60, only some of which are labeled. The coulter wheel assemblies 50 arelaterally spaced apart and are mounted in longitudinally spaced apartrows. Each coulter wheel assembly 50 is laterally spaced apart withrespect to the coulter wheel assemblies in a longitudinally adjacentrow. The conservation tillage implement further comprises a plurality ofS-tine assemblies 80 removably mounted to the transverse cross-members41 and interspersed with the coulter wheel assemblies 50. Each S-tineassembly 80 is made from a resilient spring steel. The S-tine assemblies80 are arranged in longitudinally spaced apart rows. A row of S-tineassemblies 80 is mounted along a common transverse axis with a row ofcoulter wheel assemblies 50. The S-tine assemblies 80 in a given row arestaggered with respect to the coulter wheel assemblies 50 (and/or S-tineassemblies 80, where applicable) in a longitudinally adjacent row. Theposition of the S-tine assemblies 80 is laterally adjustable on thetransverse cross-members 41.

Referring to FIG. 9, a C-shaped shank assembly 90 for use in the presentinvention is described. A C-shaped shank member 91 has at its lower enda pair of holes 92 for attachment of a ground engaging member (notshown) thereto. The C-shaped shank member 91 is pivotally attached atits upper end to a mounting means, generally shown as 93, comprising apair of L-shaped flanges 94, each flange having a complementary set ofvertically aligned mounting holes 95. A horizontal square tube 96 issecured to each L-shaped flange 94 and prevents the flanges fromrotating relative to one another. When mounted to a transversecross-member 41 (not shown in FIG. 9), the horizontal square tube 96rests against an upper surface of the transverse cross-member,vertically supporting the C-shaped shank assembly 90. A U-shaped clevis(not shown) having a pair of free threaded ends is placed over thetransverse cross-member 41 so that the free threaded ends arelongitudinally inserted through a pair of holes 95 from a given set ofholes, a clevis being provided for each L-shaped flange 94. Nuts (notshown) are tightened on to the free threaded ends to clamp the L-shapedflanges 94 against a rear surface of the transverse cross-member 41. Ashank flange 97 is mounted to the C-shaped shank member 91 below itspivotal attachment to the L-shaped flanges 94. An upwardly extendingshaft 100 is pivotally attached at its lower end to the shank flange 97and at its upper end to the L-shaped flanges 94 by means of trunnioncollar 98. A coil spring 99 is captivated between the shank flange 97and the trunnion collar 98 and is compressed upon upward deflection ofthe C-shaped shank member 91 as the shaft 100 slides within the trunnioncollar. The mounting means 93 described herein may be used as analternative to the mounting means 60 in mounting field working tools orcoulter wheel assemblies to the cultivator frame.

In FIG. 10, another embodiment of a conservation tillage implement ofthe present invention is described with reference to elements of FIGS.1-5. The cultivator frame is the frame described with reference to FIG.1 and functions in the same manner. Individual coulter wheel assemblies50 are removably mounted to transverse cross-members 41 using mountingmeans 60, only some of which are labeled. The coulter wheel assemblies50 are laterally spaced apart and are mounted in longitudinally spacedapart rows. Each coulter wheel assembly 50 is laterally spaced apartwith respect to the coulter wheel assemblies in a longitudinallyadjacent row. The conservation tillage implement further comprises aplurality of C-shaped shank assemblies 90 removably mounted to thetransverse cross-members 41 and interspersed with the coulter wheelassemblies 50. Each C-shaped shank assembly 90 is mounted using mountingmeans 93. The C-shaped shank assemblies 90 are arranged inlongitudinally spaced apart rows. A row of C-shaped shank assemblies 90is mounted along a common transverse axis with a row of coulter wheelassemblies 50. The C-shaped shank assemblies 90 in a given row arestaggered with respect to the coulter wheel assemblies 50 (and/orC-shaped shank assemblies 90, where applicable) in a longitudinallyadjacent row. The position of the C-shaped shank assemblies 90 islaterally adjustable on the transverse cross-members 41.

Referring to FIG. 11, the embodiment of the conservation tillageimplement described with reference to FIG. 7 is shown with levelingattachments, generally denoted as 101, mounted to the rear of the frame.A set of spike harrows 102 is mounted to the rear of the frame usingmounting flanges 34. A set of rolling harrows 103 is also mounted to therear of the frame using mounting flanges 34. The spike harrows 102 androlling harrows 103 are used to further kink and break the crop residueto aid in decomposition and to level the soil following the coulterwheel assemblies 50.

Referring to FIG. 12, In FIG. 10, another embodiment of a conservationtillage implement of the present invention is described with referenceto elements of FIGS. 1-5. Individual coulter wheel assemblies 50 areremovably mounted to transverse cross-members 41 using mounting means60. Five longitudinally spaced apart rows of individual coulter wheelassemblies 50 are shown. A tongue constraint 110 is pivotally attachedto the coupling mechanism 31 at constraint hinge 33. The tongueconstraint 110 is variable in length and may be adjusted to level theframe with reference to ground. A set of spike harrows 112 and a set ofrolling harrows 113 are mounted to a leveling attachment flange 111 thatis itself mounted to rear mounting flange 34. The rolling harrows 113are able to deflect upwardly in response to impact with obstacles bypivoting about their attachment to the leveling attachment flange 111.The upward deflection of the rolling harrows 113 is resisted by harrowspring 114, which is extended upon upward deflection. A rear couplingmechanism 120 is also provided for attachment of a leveling implement(not shown) to the rear of the cultivator frame.

Referring to FIG. 13, a coulter wheel assembly 150 is shown that may beused as an alternative to the coulter wheel assembly 50 in aconservation tillage implement of the present invention. The coulterwheel assembly 150 comprises a lower shank portion 153 having arotatable hub 154 rotatably attached thereto. A coulter wheel 155 havinga plurality of radial ridges alternately extending from each side of thecoulter wheel is mounted to the rotatable hub 154. The lower shankportion 153 is telescoping in length and is adjustable by means of shankbolts 156. The lower shank portion 153 is pivotally attached to theupper shank portion 152 by means of pivot plate 157. The upper shankportion 152 is circular in cross-section and may be inserted withinhollow strut 61 of mounting means 60 (not shown in FIG. 13). A hole 158is provided for receiving pin 63 when mounted using mounting means 60 inthe manner previously described with reference to FIGS. 2-5. Adeflection shaft 159 is adjustably mounted to the lower shank portion153 and is slidaby received within a trunnioned deflection collar 160offset from the upper shank portion 152. A deflection spring 161 issecured on the deflection shaft 159 at one end by the trunnioneddeflection collar 160 and at the other end by a washer 162 fixedlymounted to the deflection shaft. The length of the deflection shaft 159between the trunnioned deflection collar 160 and the point of attachmentto the lower shank portion 153 may be adjusted via deflection set nut163 to affect a desired angle between the upper shank portion 152 andthe lower shank portion. Upon impact with an obstacle, the deflectionshaft 159 slides within the trunnioned deflection collar 160 and thedeflection spring 161 is deformed, thereby urging the lower shankportion 153 to return to the desired angle.

Other advantages which are inherent to the structure will be evident toone skilled in the art.

It will be understood that certain features and sub-combinations are ofutility and may be employed without reference to other features andsub-combinations. This is contemplated by and is within the scope of theclaims.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

A person skilled in the art will recognize that variants or mechanicalequivalents may be substituted for certain of the previously describedfeatures without having an effect on the way in which the inventionworks.

What is claimed is:
 1. A method of conservation tillage comprising:providing a conservation tillage apparatus on a field comprising soiland having crop residue thereon; providing the conservation tillageapparatus with a frame having four or more rows of laterally spacedapart, laterally adjustable coulter wheel assemblies, each coulter wheelassembly comprising a resilient element and related structure to permitupward deflection of the coulter wheel in response to impact with anobstacle; individually mounting the coulter wheel assemblies to theframe such that the coulter wheel assemblies in a given row arestaggered with respect to the coulter wheel assemblies in alongitudinally adjacent row; prior to planting and while the field iswet, operating the conservation tillage apparatus on the field in orderto cut the crop residue and/or aerate the soil, thereby allowing thesoil to dry; selecting a lateral spacing between the coulter wheelassemblies that is sufficient to reduce plugging of wet soil and/or wetcrop residue between the coulter wheel assemblies; selecting anoperational depth that is sufficient to aerate the soil for plantingfrom a range of from 1″ to 4″; and, wherein the method results in anearlier planting date for the field than would be obtained without useof the method, and wherein the method results in a yield improvementwhen soybeans are planted in the field.
 2. The method according to claim1, wherein the method further comprises selecting an operating speeds offrom 8 to −20 mph, according to soil type, moisture conditions and/orcrop residue conditions.
 3. The method according to claim 1, wherein themethod further comprises: mounting each coulter wheel assembly to theframe by way of a mounting structure; permitting rotational movement ofeach coulter wheel assembly about a corresponding vertical axis passingthrough the mounting structure; and choosing to reverse a direction ofoperation of the apparatus at an end of the field without raising theapparatus and without damage to the coulter wheel assemblies by virtueof rotational movement of each coulter wheel assembly about itscorresponding vertical axis in order to at least partially fill in tireruts creating in the wet soil while turning.
 4. The method according toclaim 1, wherein the method further comprises providing the apparatuswith a set of rolling harrows and a set of spike harrows disposed at arear of the frame and configured to cut the crop residue in order to aidin drying of the wet soil and for leveling the field of any tire rutscreated in the wet soil.
 5. The method according to claim 4, wherein themethod further comprises spring-mounting the rolling harrows and spikeharrows and permitting these harrows to deflect upwardly in response toimpact with obstacles to prevent damage to the apparatus.
 6. The methodaccording to claim 1, wherein the apparatus comprises four or more rowsof coulter wheel assemblies.
 7. The method according to claim 1, whereinthe method further comprises providing each coulter wheel assembly witha single coulter wheel in order to prevent plugging of wet soil and/orcrop residue between the coulter wheels.
 8. The method according toclaim 1, wherein the lateral spacing sufficient to reduce plugging isdetermined according to soil type, moisture conditions, and/or cropresidue conditions.
 9. The method according to claim 1, wherein theapparatus further includes two sets of height-adjustable wheels, eachset comprising at least two wheels, and wherein the method furthercomprises staggering the wheels relative to one another in a walkingaxle arrangement in order to reduce the likelihood of plugging with wetsoil and/or crop residue between the wheels.
 10. The method of claim 1,wherein each resilient element includes a coil spring with a horizontalspring axis, wherein each related structure comprises upper and lowershank ends extending tangentially from the coil spring, and wherein themethod further comprises permitting upward deflection of each lowershank end in response to impact of the corresponding coulter wheel withan obstacle.